Water Security Problem in North China： Research and Perspective

This paper addresses the emergence of water security problems in North China with the aim of highlighting key water resources management and water security issues for the long-term development of North China. Three key problems related to water resources and security issues in North China in the 21st century are addressed, namely 1） the water cycle under environmental change, 2） agricultural water saving, and 3） water security. Development of international research related to these issues is also reviewed. The research plan developed recently by the Chinese Academy of Sciences （CAS） is discussed and suggestions on research and development of water resources science in North China are presented. Thanks to focus on experimental catchments and dedicated research stations, a detailed knowledge of the water cycle on North China farmland has been compiled. A range of techniques that include isotope tracers has been used to acquire hydrologic data. Much research has been devoted to developing distributed hydrological models at different scales. In the well irrigation district, five different water saving irrigation regimes have been investigated, and these regimes have had widespread application, and reduced water use 60-150 mm while they increased water use efficiency （WUE） by 20%-30%. Furthermore, preventing water pollution is the most essential step to ensure North China＇s water security.     

亏缺灌溉对中国西北干旱区棉花生长、水分利用特征和产量的影响

Water shortage is a key constraint to sustainable agricultural production in Xinjiang, Northwest China. To enhance the use efficiency of valuable irrigation water resources, a 2-year experiment(2010–2011) was conducted to quantify the response of cotton(Gossypium hirsutum L.) growth and yield to different degrees of deficit irrigation(DI) regimes; to determine the effects of DI on the characteristics of water use for cotton, seasonal water use, available soil water in the root zone, soil water depletion, evapotranspiration(ET)-based water use efficiency and irrigation-based water use efficiency, and to determine the best DI regime for optimal water-saving and yield output. The plots were irrigated at 100%(100ET), 85%(85ET), 70%(70ET), 55%(55ET) and 45%(45ET) of the regional ET of cotton in northern Xinjiang. The effect of DI irrigation on water use characteristics was evaluated by analyzing available soil water and soil water depletion in the root zone along with water use efficiencies of cotton. The study showed that the growth, water use characteristics and yield of cotton varied with irrigation regime. Seasonal ET and seed cotton yield were linearly correlated with irrigation amount. The second-order polynomial equation best approximated water-yield relationship of cotton in the study area.Cotton yield response factor was 0.65, suggesting limited water conditions were suitable for cotton cultivation. Economic evaluation of DI treatments confirmed that the yield loss was less than 10% under 70 ET and 85 ET, which was acceptable for greater sustainability.The results suggested that proper DI schemes were necessary for sustainable cotton production in the region. While irrigation at 85 ET was safe for high cotton yield, irrigation at 70 ET was a viable alternative under limited irrigation water availability.     

中国化肥使用带来的环境问题

The current status of chemical fertilizers production and consumption in China as well as their important roles in Chinese modern agriculture are discussed with special concerns to the environmental issues related to chemical fertilizer use.On the one hand.the total amount of chemical fertilizer produced is insufficient to meet the agricultural needs.On the other hand.the production and consumption of chemical fertilizers in China are obviously not balanced.In some areas over application of nitrogen fertilizers and loss of phosphate fertilizer due to soil erosion have resulted in some undesirable environmental problems such as increase of nitrate in water and eutrophication of water bodies.Maximum scientific uses of organic manures in combination with reasonable use of chemical fertilizers are part of good practices not only in increasuing soil productivity and keeping sustainable agriculture development but also in minimizing their detrimental effects on the environment.     

地膜覆盖滴灌棉田土壤上水分动态的数值模拟

Drip irrigation under plastic mulch has been widely applied in arid Northwest China as a water-saving irrigation technology.A comprehensive knowledge of the distribution and movement of soil water in root zone is essential for the design and management of irrigation regimes.Simulation models have been proved to be efcient methods for this purpose.In this study,the numerical model Hydrus -2D was used to simulate the temporal variations of soil water content in a drip irrigated cotton field under mulching.A concept of partitioning coefcient,calibrated to be 0.07,was introduced to describe the efect of plastic mulch on prevention of evaporation.The soil hydraulic parameters were optimized by inverse solution using the field data.At the optimized conditions,the model was used to predict soil water content for four field treatments.The agreements between the predictions and observations were evaluated using coefcient of determination (R2) and root mean square error (RMSE).The results suggested that the model fairly reproduced the variations in soil water content at all locations in four treatments,with R2 ranging from 0.582 to 0.826 and RMSE from 0.029 to 0.050 cm3 cm-3,indicating that the simulations agreed well with the observations.     

控制中国非点源污染的生物经济学战略

While non-point pollution from agriculture has become an increasingly serious problem in China, some progress has been made in studying the causal biophysical processes. However, few studies have assessed the economic consequences of non-point pollution in China or the policy options that could be employed to combat it. In this work a sustainable strategy to control non-point pollution from crop production, which involved taxing excessive inputs of irrigation water and fertilizer, was proposed. The approach taken to assess these measures combined biophysical and economic models,having a trade-off between economic returns and an improved environment. A proven and practical spatially referenced water and nutrient management model was used to determine the quantities of excessive irrigation water and fertilizer for specific soil and land use. Also, a set of indicators were proposed for evaluating the effects of agricultural economic output and agricultural practices on the environment.     

高速发展的东南沿海地区资源与环境质量变化与可持续发展调整战略

Problems in water-land resources and environmental quality increase with the fast economic development in the coastal region of southeastern China,This region has the highest density in population,industry and towns in China,and the large export-oriented economy makes itself a strategic importance while China enters into international markets.The problems facing to this region include arable land reduction,land degradation aggravation,high percentage of built-up land with high rate of expansion,expanded non-point pollution,deteriorated water quality,decreasing biodiversity,destroyed ecosystems,sever air pollution,frequently occurred acid rain,and multi-pollutants.The important reaarch fields in the near future should include a )influence of high-intensity exploitaion of resources on changes of environment quality and its feedback;b) influence processes ,key mechanisms and adjustment principles for degradation of water,land-,and air-resources and environmental quality;c)evolvement processes and nurturing theory of bioiversity and ecological resourcs;and d) spatio-temporal variaiton and human-induced effects on regional resources and environment quality .Strategies for sustainable development in the region are as follows:a) controlling to ensure basic cultivated land area;b) enforcing remediation of polluted water environment,and controlling non-point pollution;c) strengthening ecological construciton and ecological security;and d) controlling multi-pollution and preventing trace toxic pollutants.     

Land use effects on the dynamics of soil C, N and microbes in the water-wind erosion crisscross region of the northern Loess Plateau, China

The water-wind erosion crisscross region of the northern Loess Plateau in China is under constant pressure from severe erosion due to its windy and dry climate and intensive human activities. Identifying sustainable land use patterns is key to maintaining ecosystem sustainability in the area. Our aim was to appraise the impacts of different land use regimes on the dynamics of soil total organic C(TOC), total N(TN), and microbes in a typical watershed in the northern Loess Plateau to identify sui...     

植物对镉毒害的形态和生理响应研究进展

Cadmium (Cd) contamination has posed an increasing challenge to environmental quality and food security.In recent years,phytoremediation has been particularly scrutinized because it is cost-effective and environmentally friendly,especially the use of metal-hyperaccumulating plants to extract or mine heavy metals from polluted soils.Under Cd stress,responses of hyperaccumulator and non-hyperaccumulator plants differ in morphological responses and physiological processes such as photosynthesis and respiration,uptake,transport,and assimilation of minerals and nitrogen,and water uptake and transport,which contribute to their ability to accumulate and detoxify Cd.This review aims to provide a brief overview of the recent progresses in the differential responses of hyperaccumulator and non-accumulator plants to Cd toxicity in terms of growth and physiological processes.Such information might be useful in developing phytoremediation technology for contaminated soils.     

Land Use Changes of Mata Lake Using Multi-temporal Satellite Imageries

Land use and protection has become a global hotspot. How to use land resources is an important topic for the future socio-economic sustainable development. This paper analyzes the land use changes of Mata lake of Shandong province in China, from 19.85＇s to 2000＇s using multi-temporal remotely sensed data including TM in the 1985s, ETM＋ in the 2000s and ancillary data such as soil use map, water map etc. the remote sensing imageries were calibrated, registered and geo--referenced, then classified by multi-source information data and remote sensing image interpretation expert system based on knowledge base. Five land use types were extracted from remote sensing imageries, that is, water body, agriculture land, rural settlement, bare land and none use land. The total precision is 80. 7% and Kappa index is 0. 825. The analysis result of the remote sensing shows that during the past 15 years, water resource dropped off very promptly from 51.77 km^2 to 16.65 km^2 and bare land reduced greatly more than 60% in Mata lake region. With the development of the economy and agriculture areas, more and more water body and bare land converted to agriculture land use and rural settlement areas. Since last years, the Mata lake has been affected by natural factor, human activity and increasing population. So its land use pattern greatly changed from 1985 to 2000. The information of land use changes provided scientific supports for land planning and environmental protection.     

作物水分敏感指数降尺度的单调分段三次插值方法

Crop-water production functions quantitatively describe the relationship between crop yield and field evapotranspiration.The crop water sensitivity indexes of crop-water production functions,a key factor for optimizing irrigation scheduling in case of water scarcity,are usually obtained from field experiments or other sources for crop growth stages,while their values in shorter intervals are preferred for practical irrigation scheduling.We proposed a method to downscale the sensitivity index from growth stages to shorter intervals by monotone piecewise cubic interpolation of the cumulative sensitivity index curve.This method was used to estimate sensitivity indexes in irrigation intervals of about 10 d for corn and wheat in central Shanxi Province of China.Results showed that the downscaled sensitivity index could reflect the impact of water stress on crop growth both at diferent growth stages and within each stage.Scenario analysis of water stress at a single growth stage of wheat showed the rationality of downscaling water sensitivity index from growth stages to shorter intervals through interpolation of cumulative sensitivity index,and this proposed downscaling method was superior to the traditional linear downscaling method.     

中国农业水问题: 若干研究重点与讨论

农业用水是水资源的主要消耗方式,尤其在华北地区,因地表水资源不足,大量农田灌溉导致地下水超采现象严重;而社会经济的快速发展和气候变化加剧了水资源的不足。水循环过程是农业节水的科学基础。从水循环过程出发,开展水量转化研究,在农田水文过程界面加以调控,进行系统的节水研究,是节水研究的重点。重视水资源的科学管理,提高水分利用效率,建立节水农业的市场机制,促进节水设施建设;同时深入开展水循环的基础研究,充分利用非传统水资源,是解决我国农业水问题的有效途径。     

井渠结合灌区用水效率指标尺度效应研究框架

现有灌溉用水效率尺度效应的研究大部分集中在地表水灌区,而较少涉及地下水利用灌区,该文针对井渠结合灌区存在地下水回归利用的实际情况,以河北省石津灌区为背景,在国际水管理研究院（IWMI）提出的水收支方法的基础上引入回归水利用指标,提出了在井渠结合灌区进行用水效率指标尺度变化规律研究的工作框架。在所提出的框架中,评价指标选择IWMI体系,数据获取手段主要为资料收集和试验观测,尺度划分方式按照现有灌区管理模型分为灌区,干渠,分干,支渠和田间5个尺度。研究成果展现了灌溉用水效率尺度效应研究所涉及到的指标选取、尺度划分、水收支解析、水平衡要素数据获取方式、回归水分析5个方面的工作过程。该框架对于开展中国北方井渠结合灌区的节水灌溉尺度效应研究有着一定的参考价值和借鉴意义。     

Saving Irrigation Water for Winter Wheat with Phosphorus Application in the North China Plain

Conserving irrigation water resources is a most important measure for sustainable wheat production in the North China Plain. In the present study, the effect of phosphorus (P) application for saving irrigation water was evaluated. The application of fertilizer P increased nitrogen and phosphorus uptake, shoot biomass, head number, seed number and, consequently, grain yield, and increased soil water use and seasonal evapo-transpiration. The lower the volume of irrigation water applied, the more obvious were these effects. When winter wheat was basally fertilized with 88.5 kg P₂O₅/ha and irrigated with 90 mm at the jointing stage, the highest fertilizer P use efficiency, apparent P recovery and net profit (due to irrigation and/or fertilizer P) were obtained. The results suggested that fertilizer P should be used for saving irrigation water resources in the North China Plain.     

我国水资源利用现状与节水灌溉发展对策

在分析我国水资源和农业用水现状的基础上,探讨农田灌溉节水途径与技术措施,提出根据经济现状,提高水的利用率和利用效率,发展节水灌溉应重点普及输水节水技术,加强地面灌水技术和节水灌溉制度的研究与推广,适度发展喷、微灌技术,并注重各项节水技术措施的综合集成,实现农田灌溉各个环节上的全方位节水     

水安全与粮食安全

水安全是粮食安全的基础,实现农业水资源的高效利用是保障水安全和粮食安全的根本途径。本文阐述了水安全与粮食安全的概念;分析了全球及我国水安全与粮食安全现状和未来形势;辨析了粮食安全的水资源保障战略的构成要素及我国节水农业的发展重点;并就粮食生产的水资源高效利用、水资源高效配置与调控、农业水资源消耗的生态环境效应以及应对旱涝极端气候等进行了讨论,进而对主要科学问题进行了归纳,包括作物理想耗水与多过程协同调控机制、强人类活动下灌区多尺度水循环与伴生过程、粮食生产-水资源-生态过程的互馈机制以及农业旱涝致灾机理与预警机制。     

基于HYDRUS-1D模型的华北低平原区不同微咸水 利用模式下土壤水盐运移的模拟

华北低平原区深层地下水的不断超采不仅造成淡水资源的枯竭,还引发了地面沉降、土壤盐渍化等一系列生态环境问题。微咸水在农业上的利用已成为缓解水资源危机的研究重点。为了研究不同咸水灌溉模式的可持续性,本文以华北低平原区的河北省南皮县为例,利用Hydrus-1D模型,基于8种不同微咸水灌溉方案,模拟2008—2013年6年冬小麦-夏玉米轮作制度下,2 m土体水盐通量变化。模拟结果表明,土体剖面盐分积盐区主要集中在下层土壤(100~200 cm);上层土壤(0~100 cm)溶液盐分浓度大部分时间保持在2 g·L~(-1)左右,能保证作物正常生长;但土壤剖面盐分浓度在冬小麦灌浆末期出现峰值且随灌水盐分浓度增加而逐渐升高。土体盐分充分淋洗的关键在于降雨强度,7月份降雨强度是土体脱盐与否的主要影响因素;同时,在丰水年型夏玉米播种后结合出苗水适当灌溉洗盐对土体达到有效脱盐起到重要作用。本文通过综合分析水文年型、土壤剖面盐分的动态分布特征以及结合夏玉米出苗水的洗盐淡水用量3方面因素对土壤盐分迁移的影响,提出华北低平原区两种适宜的微咸水灌溉制度:(1)冬前浇灌小于2 g·L~(-1)的冬小麦越冬水,春后在冬小麦拔节期浇灌一次2~4 g·L~(-1)微咸水;(2)冬前不灌越冬水,春后分别在冬小麦拔节期和灌浆期浇灌2 g·L~(-1)微咸水。两种灌溉制度年均结合夏玉米出苗水的洗盐淡水用量和总耗水量分别为60~70 mm和250~260 mm。本文结果旨在为华北低平原区微咸水利用的节水潜力及其可持续性提供理论指导。     

关于节水灌溉技术规范中确定若干技术指标的意见

围绕节水灌溉技术参数的合理选择,从我国水资源状况、农业用水需求、灌溉水平、节水灌溉面临的形势与任务等角度简述了该项研究的必要性,分析了国内外农田灌溉用水标准方面的现状,介绍了节水灌溉技术参数合理选择研究的主要内容,对节水灌溉节水增产指标、渠道防渗率指标、畦田规格等若干重要指标的取值作了详细说明。     

雨养区水保型高效生态农业建设探索

雨养区大部分干旱缺水、土地瘠薄、水土流失严重、粮食产量低而不稳、生态环境恶劣。建立生态农业是实现雨养农业区社会、经济持续发展的唯一出路,而搞好水土保持,充分利用水资源、土地资源,加大农业科技投入是建立雨养区生态农业的关键。在水资源方面主要抓好储蓄水、保持水、节约水;在土地资源方面主要抓好：（１）调整土地利用结构和梯田工程建设,（２）庭院经济和“四荒”地的开发利用,（３）加大肥力投入;在农业科技方面主要抓好地膜覆盖技术、集流节灌技术、抗旱丰产技术等。     

干旱内陆河流域下游绿洲生态建设中的水资源问题

在研究干旱内陆河流域下游绿洲生态建设方向与重点的基础上,提出了生态系统和生态用水量分级管理和规划的思想,探讨了其所涉及的重要的水安全与生态安全、水资源产权管理与核算、水资源配置管理、水资源政策管理、水资源开发利用管理、生态用水与水资源承载能力、人工草场与节约用水、绿洲边缘半荒漠草场的保护治理与用水等8个方面的水资源问题,提出了干旱内陆河流域下游绿洲可持续发展的重大战略对策。     

对建设关中节水型灌区的思考

从降水资源、地表水资源、地下水资源等方面分析了关中地区水资源的现状。指出了该区域在传统灌溉模式下现存的效率低下等问题。提出了将关中地区建设成节水型灌区的构想和措施。提出要尽快制定节水灌区的建设标准,重视输水过程中的节水和改进灌溉方式,重视生物节水,推广有限灌溉,提高水资源利用率,提高农艺节水,推广地表防止蒸发措施,提高水分利用率,开源节流,扩大非常规水资源利用。这些措施是建设节水型灌区的关键,也是实现水资源可持续发展的基本措施。